Dental syringe

ABSTRACT

A dental syringe may include a replaceable valve cartridge containing one or more valves which may use a seating surface and an opposing seating surface with a relative angle formed between the two surfaces. The relative angle allows for regulation of the flow of fluid. The replaceable valve cartridge may also include a system to remove a residual liquid from a tip of a dental syringe. Additionally, the replaceable valve cartridge may include a seal that prevents bleed-over of fluids. Further, the dental syringe may comprise a tip retention insert which may use either a pair of plates or a plurality of ball bearings to retain the dental syringe tips. An alternate embodiment of a valve may comprise features intended to reduce the force necessary to actuate the valve. A metering screw and/or flow-control groove with increasing depth may control of flow through the valve.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application No.61/171,272, filed Apr. 21, 2009 and U.S. Provisional Application No.61/288,691, filed Dec. 21, 2009, both of which are hereby incorporatedherein in their entirety by reference.

BACKGROUND

1. Field of the Invention

Embodiments of the invention relate to dental syringes and correspondingapparatuses and methods.

2. Description of Related Art

Dental syringes are known tools within the medical and dental industriesthat are typically used to supply air, water, heated water, medicine, ora combination thereof to the oral cavity. A dental syringe can also beused to evacuate the oral cavity by providing a vacuum function. Dentalsyringes can be used to clean and remove unwanted substances fromtargeted areas of the oral cavity such as saliva, blood, or debrisresulting from procedures carried out on portions of the oral cavity. Adental syringe tip having one or more channels defined therein connectswith the dental syringe and provides a way to direct the fluids from thedental syringe to specific areas of the oral cavity. The syringe tip maybe replaceable from the body of the syringe after the syringe tipbecomes contaminated or damaged, or as a precautionary measure. Suppliesof pressurized water and air connect to the syringe to provide thefluids necessary for operation of the dental syringe.

BRIEF SUMMARY

A dental syringe may include a replaceable valve cartridge containingone or more valves which may use a seating surface and an opposingseating surface with a relative angle formed between the two surfaces.The relative angle allows for regulation of the flow of fluid. Thereplaceable valve cartridge may also include a system to remove aresidual liquid from a tip of a dental syringe. Additionally, thereplaceable valve cartridge may include a seal that prevents bleed-overof fluids. Further, the dental syringe may comprise a tip retentioninsert which may use either a pair of plates or a plurality of ballbearings to retain the dental syringe tips. An alternate embodiment of avalve may comprise features intended to reduce the force necessary toactuate the valve. A metering screw and/or flow-control groove withincreasing depth may control of flow through the valve.

Embodiments of the invention may comprise a flow regulating valvecomprising a body defining a flow passageway, a piston extending throughthe flow passageway and defining an axis, a spring configured to apply aspring force on the piston in a first direction along the axis, aseating surface of at least one of the piston and the body which maycomprise a first sloped surface, and an opposing seating surfacereleasably sealable against the seating surface by the spring force andsubstantially blocking the flow passageway. Additionally, the seatingsurface and the opposing seating surface may be cooperatively configuredto partially release the opposing seating surface from the seatingsurface when a first opposing force is applied to displace the piston ina second direction, substantially opposite to the first direction, tothereby partially open the flow passageway. When a second opposingforce, which is larger than the first opposing force, is applied, theopposing seating surface may completely release from the seating surfaceto thereby further open the flow passageway.

Alternate embodiments of flow regulating valves comprise a body defininga flow passageway, a flow-control seal positioned within the flowpassageway, a flow passageway end seal positioned within the flowpassageway; and a piston defining a flow-control groove extendingthrough the flow passageway, the flow passageway end seal, and theflow-control seal, the piston defining a first direction and a seconddirection of an axis, wherein the flow passageway end seal is positionedin the second direction from the flow-control seal. A fluid supplyconduit is in fluid communication with a first portion of the flowpassageway defined between the flow control seal and the flow passagewayend seal, wherein the fluid supply conduit is configured to provide afluid flow applied at the perimeter of the piston in the first portionof the flow passageway. A fluid outlet conduit may be in fluidcommunication with a second portion of the flow passageway, and a springpositioned in a cavity or other force means may be configured to apply aforce on the piston in the first direction (outward) along the axis oftravel. In some embodiments the force means comprises a fluid sourceconfigured to supply a fluid force to the piston.

The flow-control seal contacts the body and the piston and therebyseparates the first portion and the second portion of the flowpassageway to substantially prevent fluid communication between thefirst portion and the second portion of the flow passageway when thepiston is in a first position wherein the flow-control groove isdisplaced from the flow-control seal in the first direction. When thepiston is displaced in the second direction (inward), substantiallyopposite to the first direction to a second position, the flow-controlgroove extends at least partially beyond the flow-control seal in boththe first and second directions, whereby the fluid supply conduit is influid communication with the fluid outlet conduit through the firstportion and the second portion of the flow passageway. A second flowpassageway end seal may be configured to substantially prevent fluidfrom escaping out of the flow passageway in the first direction. Theflow-control groove may be configured to permit increasing flow of fluidthrough the valve as the piston is displaced in the second direction. Insome embodiments at least a portion of the piston at the flow-controlgroove may define a plurality of cross-sections perpendicular to theaxis of the piston which generally decrease in area from the farthestportion of the flow-control groove in the second direction towards thefirst direction until a maximum groove depth is reached, which may allowfor more precise flow control.

A first centering sleeve may be positioned within the flow passagewaywith the piston extending through the first centering sleeve to therebysubstantially prevent movement of the piston other than in the first andsecond direction. The first centering sleeve may be positioned in thefirst portion of the flow passageway, and the first centering sleevecomprises an inlet aperture through which fluid communication betweenthe fluid supply conduit and the flow-control groove occurs when thepiston is displaced in the second direction. A second centering sleevemay be positioned within the second portion of the flow passageway,wherein the second centering sleeve comprises an outlet aperture throughwhich fluid communication between the flow-control groove and the fluidoutlet conduit occurs when the piston is displaced in the seconddirection.

The flow control valve may comprise features intended to reduce theactuation force necessary to operate the flow control valve. Forexample, the cavity may be in communication with a cavity pressure,wherein the cavity pressure is less than the pressure in the fluidsupply conduit such as when the cavity pressure is ambient air pressure.In particular, the cavity may be in communication with ambient airpressure through a pressure relief conduit. Further, the fluid supplyconduit may be substantially out of fluid communication with the distalends of the piston. Further, the total area of the piston perpendicularto the axis which is exposed to force from the fluid in the seconddirection may be greater than, less than, or equal to the total area ofthe piston perpendicular to the axis which is exposed to force from thefluid in the first direction.

The flow control valve may further comprise a first retaining member,the first retaining member extending at least partially through the bodyand at least indirectly contacting the first centering sleeve to therebyrestrain movement of the first centering sleeve and the flow-controlseal at least in the first direction. The flow control valve may alsocomprise a second retaining member, the second retaining member couplingto the piston in the cavity, whereby movement of the piston in the firstdirection is at least partially restrained by indirect contact betweenthe second retaining member and the first retaining member through atleast the centering sleeve and the flow-control seal.

A method of controlling a flow of fluid is also provided. The method mayinclude providing a valve comprising a piston defining a flow-controlgroove and extending through a flow passageway defined in a body and aflow passageway end seal and a flow-control seal positioned within theflow passageway, wherein the flow-control seal separates the flowpassageway into a first portion, defined between the flow-control sealand the flow passageway end seal, and a second portion and providing aforce means configured to apply a force to the piston in a firstdirection along an axis of travel defined by the piston. The method mayfurther comprise displacing the piston in a second direction along theaxis of travel opposite to the first direction to bring the firstportion and the second portion of the flow passageway into fluidcommunication through the flow-control groove and thereby allow fluid toflow through the valve and releasing the piston, whereby the force meansdisplaces the piston including the flow-control groove in the firstdirection and thereby prevents fluid communication between the firstportion and the second portion of the flow passageway and prevents flowof fluid through the valve.

In some embodiments the fluid supply conduit may comprise a meteringscrew, the metering screw comprising a cylindrical end portion which isconfigured to be received by a metering cavity in the body, the meteringcavity comprising a cylindrical end cavity. The cylindrical end portionis moveable from an extended position to a retracted position, whereinwhen the cylindrical end portion is in the extended position, themetering screw occupies a first occupied volume of the metering cavity,and wherein when the cylindrical end portion is in the retractedposition, the metering screw occupies a second occupied volume of themetering cavity. The second occupied volume may be less than the firstoccupied volume, and the fluid supply conduit is in fluid communicationwith the first portion of the flow passageway when the cylindrical endportion is in the extended position and the retracted position.Alternate embodiments of metering screws are also provided. In one suchembodiment the metering screw comprises a threaded portion defining afirst end rotatably operable by a user and a second end defining acavity, and a compressible cylindrical end portion received within thecavity defined by the second end of the threaded portion and extendingtherefrom along an axis. The compressible cylindrical end portion maydefine a spherical end. There is further provided, a fluid flow meteringsystem comprising a metering screw configured to be received by a bodydefining a metering cavity. The fluid flow metering system comprises athreaded portion configured to screw into a threaded receiving portionof the metering cavity, and a compressible cylindrical end portioncoupled to the threaded portion and moveable along an axis between anextended position and a retracted position in a cylindrical end cavitydefined by the metering cavity. When the compressible cylindrical endportion is in the extended position, the compressible cylindrical endportion is compressed along the axis and radially expanded tosubstantially seal against the cylindrical end cavity to substantiallyprevent flow of a fluid therethrough. Further, when the compressiblecylindrical end portion is in the retracted position, the compressiblecylindrical end portion is at least partially out of contact with thecylindrical end portion to allow flow of the fluid therethrough.

In additional embodiments of the invention, a replaceable valvecartridge for a dental syringe may comprise a housing which contains oneor more valves, and a seal for sealing an axially inserted dentalsyringe tip.

Further embodiments of the invention may include a replaceable tipretention insert for a dental syringe, comprising a housing at leastpartially defining a cavity configured for insertion of a dental syringetip, one or more clamping members moveably positioned around the cavity,one or more springs configured to bias the clamping members at leastpartially into the cavity, and at least one releasable cartridgeretainer configured to releasably hold the replaceable tip retentioninsert in a head of the dental syringe. The clamping members maycomprise a first plate and a second plate. Alternatively, the clampingmembers may comprise a plurality of ball bearings, wherein the springsprovide a radially inwardly directed force on each of the spheres.

Additional further embodiments of the invention may comprise a seal forsealing an axially inserted dental syringe tip configured to direct afirst fluid through a first fluid path, direct a second fluid through asecond fluid path, prevent bleed-over of the first fluid into the secondfluid path, and prevent bleed-over of the second fluid into the firstfluid path. Such embodiments may comprise a first channel definedbetween a first ring of a first elastic portion and a second ring of asecond elastic portion, and a bleed path. The first channel may beconfigured to be in fluid communication with the bleed path, andconfigured to permit any of the first fluid and the second fluid whichreaches the first channel to exit through the bleed path.

Alternate embodiments of the invention may comprise a system to remove aresidual liquid from a tip of a dental syringe having supplies of aliquid and a second fluid thereto. These embodiments may comprise a bodydefining a cavity comprising an inlet, an outlet, and an outlet sealingsurface, a moveable stopper located within the cavity and configured tobias against the outlet sealing surface by the second fluid so as to atleast partially seal the outlet, and a plunger configured to move in afirst direction along a longitudinal axis of the plunger to displace thestopper from the outlet sealing surface and further configured to movein a second direction, substantially opposite to the first direction,such that the outlet is in fluid communication with the tip of thedental syringe.

Other embodiments of the invention may comprise a method of removing aresidual liquid from a tip of a dental syringe having supplies of aliquid and a second fluid thereto. Such embodiments may compriseactuating a single actuator to dispense the liquid from the tip of thedental syringe and automatically dispensing the second fluid out of thetip of the dental syringe following the dispensing of the liquid. Thedispensing of the second fluid may substantially remove the residualliquid from the tip of the dental syringe.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 illustrates a partially transparent side view of an embodiment ofa dental syringe;

FIG. 1A illustrates a perspective view of the dental syringe of FIG. 1showing back and side portions;

FIG. 1B illustrates a perspective view of the dental syringe of FIG. 1showing front and side portions;

FIG. 2 illustrates a cross-sectional view of an embodiment of a flowregulating valve having a plug serving as a body with a sloped seatingsurface within a replaceable valve cartridge for a dental syringe;

FIG. 2A illustrates a schematic representation of an embodiment of aflow regulating valve having a body with a sloped seating surface in aclosed position;

FIG. 2B illustrates a schematic representation of the embodiment of aflow regulating valve of FIG. 2A having a body with a sloped seatingsurface in a partially open position;

FIG. 2C illustrates a schematic representation of the embodiment of aflow regulating valve of FIG. 2A having a body with a sloped seatingsurface in a fully open position;

FIG. 2D illustrates a schematic representation of an embodiment of aflow regulating valve having a piston with a sloped seating surface in aclosed position;

FIG. 2E illustrates a schematic representation of an embodiment of aflow regulating valve having a first sloped seating surface and a secondsloped opposing seating surface in a closed position;

FIG. 2F illustrates an enlarged portion of the flow regulating valve ofFIG. 2;

FIG. 2G illustrates an alternate embodiment of a flow regulating valve;

FIG. 2H illustrates an alternate cross-sectional view of the flowregulating valve of FIG. 2G;

FIG. 2I illustrates a modified cross-sectional view of the flowregulating valve of FIG. 2G from an alternate perspective in a firstposition, which substantially prevents flow;

FIG. 2J illustrates a modified cross-sectional view of the flowregulating valve of FIG. 2G from an alternate perspective in a secondposition, which allows flow;

FIG. 2K illustrates an enlarged alternate cross-sectional view of theflow regulating valve of FIG. 2G in the second position;

FIG. 2K′ illustrates an enlarged alternate cross-sectional view of theflow regulating valve of FIG. 2G in the second position, including thefluid outlet conduit;

FIG. 2K″ illustrates a piston comprising the flow regulating valve ofFIG. 2G;

FIG. 2K′″ illustrates a cross-sectional view along the length of thepiston of FIG. 2K″;

FIG. 2K″″ illustrates a an enlarged view of the section B from FIG. 2K′″showing a groove defined in the piston;

FIG. 2K′″″ illustrates a cross sectional view through the groove fromFIG. 2K″″;

FIG. 2L illustrates a cross-sectional view of a metering screw in anextended position which allows a relatively small flow;

FIG. 2M illustrates a perspective view of an embodiment of a meteringscrew of with a compressible cylindrical end portion in the head portionof a dental syringe;

FIG. 2N illustrates the metering screw of FIG. 2L in a retractedposition which allows a relatively large flow;

FIG. 2O illustrates an alternate perspective of the metering screw ofFIG. 2M in the head portion of a dental syringe.

FIG. 3 illustrates a side view of an embodiment of a replaceable valvecartridge;

FIG. 3A illustrates a side view of the replaceable valve cartridge ofFIG. 3 positioned within a head portion of a dental syringe shown inpartial transparency;

FIG. 3B illustrates a perspective view of the bottom and back of anembodiment of a replaceable valve cartridge;

FIG. 3C illustrates a perspective view of the front of the replaceablevalve cartridge of FIG. 3B;

FIG. 4 illustrates a perspective view of the side and front of anembodiment of a head portion of a dental syringe having a tip retentioninsert;

FIG. 4A illustrates a perspective view of a tip retention insert of FIG.4;

FIG. 4B illustrates a perspective view of the side and front of the headportion of FIG. 4 wherein the head portion is shown in partialtransparency;

FIG. 4C illustrates a cross-sectional view of the tip retention insertof FIG. 4 in an open position;

FIG. 4D illustrates a cross-sectional view of the tip retention insertof FIG. 4 in a closed position with a regular dental syringe tip;

FIG. 4E illustrates a cross-sectional view of the tip retention insertof FIG. 4 in a closed position with an indexing dental syringe tip;

FIG. 4F illustrates a front schematic view of a first plate of the tipretention insert of FIG. 4;

FIG. 4G illustrates a front schematic view of a second plate of the tipretention insert of FIG. 4;

FIG. 4H illustrates a cross-sectional view of a tip retention insertwith intermediate and distal locking sections in an open position;

FIG. 4I illustrates a cross-sectional view of the tip retention insertof FIG. 4H in a closed position with a regular tip secured therein;

FIG. 4J illustrates a cross-sectional view of the tip retention insertof FIG. 4H in a closed position with an indexing tip locked therein;

FIG. 4K illustrates a cross-sectional view of an additional embodimentof a tip retention insert comprising ball bearings and a springcontacting one button;

FIG. 4L illustrates a modified cross-sectional view of the embodiment ofa tip retention insert of FIG. 4K showing comprising ball bearings and aspring;

FIG. 5 illustrates a modified cross-sectional view of a seal for sealinga dental syringe tip in a replaceable valve cartridge;

FIG. 5A illustrates a perspective view of the seal for sealing a dentalsyringe tip in a replaceable valve cartridge of FIG. 5 with thereplaceable valve cartridge shown in partial transparency;

FIG. 5B illustrates a modified cross-sectional view of the seal forsealing a dental syringe tip in a replaceable valve cartridge of FIG. 5with the replaceable valve cartridge shown in partial transparency;

FIG. 5C illustrates an alternate embodiment of a seal for sealing adental syringe tip and fluid flow patterns therethrough;

FIG. 6A illustrates a modified cross-sectional view of an embodiment ofa system for removing a residual liquid from the tip of a dental syringeand showing the positioning of the elements of the system before aliquid has been dispensed from the dental syringe ;

FIG. 6B illustrates a cross-sectional view of the system of FIG. 6Ashowing the positioning of the elements of the system while the liquidis being dispensed and hence the moveable stopper has been displacedfrom the outlet sealing surface;

FIG. 6C illustrates a cross-sectional view of the system of FIG. 6Ashowing the positioning of the elements of the system when the liquid isno longer being dispensed and hence a puff of fluid is being released;

FIG. 6D illustrates a cross-sectional view of an additional embodimentof a system for removing residual liquid from a tip of a dental syringein which an opening through the plunger defines a flow path;

FIG. 7A illustrates a flow chart of a first method for removing aresidual liquid from the tip of a dental syringe; and

FIG. 7B illustrates a flow chart of a second method for removing aresidual liquid from the tip of a dental syringe.

DETAILED DESCRIPTION

The present inventions now will be described more fully hereinafter withreference to the accompanying drawings, in which some, but not allembodiments of the inventions are shown. Indeed, these inventions may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

FIG. 1 illustrates an embodiment of a dental syringe 100. The dentalsyringe 100 may also be referred to as a 3-way syringe because thedental syringe may be configured to provide a flow of a first fluid, asecond fluid, or a combination thereof, such as air, water, or a mist ofboth air and water. Other fluids may also be dispensed by the dentalsyringe 100. The dental syringe 100 may generally comprise a handleportion 102 and a head portion 104, which join together. The connectionbetween the head portion and handle portion may occur through a varietyof known means including threaded connections and frictionalrelationships such as through use of one or more o-rings, as may beapparent to one of ordinary skill in the art. The head portion mayinclude one or more buttons 103 and a button retaining pin 105. Thedental syringe 100 may further comprise a replaceable valve cartridge106 and a replaceable tip retention insert 108 for retaining a dentalsyringe tip 110.

FIG. 1A illustrates the embodiment of the dental syringe of FIG. 1 froma perspective showing a side, top, and rear of the dental syringe 100.This embodiment shows the handle portion 102 with the attached headportion 104. The head portion comprises a pair of buttons 103 held in bya button retaining pin 105. As may be apparent to one having ordinaryskill in the art, the buttons could be held in place by a single pin, aplurality of pins, or one or more other similar devices which preventthe buttons from falling out. The head portion further includes areplaceable tip retention insert 108 for retaining a dental syringe tip110.

FIG. 1B illustrates the embodiment of the dental syringe of FIG. 1 froma perspective showing the side and front of the dental syringe 100. Thisembodiment includes a handle portion 102 with an attached head portion104. The head portion comprises one or more buttons 103 held in by abutton retaining pin 105. The head portion further includes areplaceable tip retention insert 108 for retaining a dental syringe tip110.

FIG. 2 illustrates a cross-sectional view of a replaceable valvecartridge 206 comprising a flow regulating valve 212. The flowregulating valve 212 is designed to regulate the flow of a fluid whichin various embodiments may be, for example, water or air. The flowregulating valve 212, as shown in greater detail in FIG. 2F, maycomprise a body 214 which in this embodiment is a plug inserted into thehousing 216 of the replaceable valve cartridge 206 and held in place bya plug retaining ring 232, as, for example, by a frictional force. Thebody 214 defines a flow passageway 218. A piston 220 extends through theflow passageway 218 along an axis 222 corresponding to the lengthwisedirection of movement of the piston passing through the flow passageway.A spring 224 is configured to apply a spring force on the piston 220 ina first direction along the axis 222 tending to push the piston in thedirection of fluid flow through the flow passageway 218, which in FIG. 2is an upward direction. By application of the spring force, an opposingseating surface 226 defined by the piston 220 is forced into sealingrelation with a seating surface 228 of the body 214, which in FIG. 2 isa sloped surface defined by the body. Because the sloped surface ofseating surface 228 is an open end of body 214 having a cylindricalshape, the sloped surface of the seating surface may define an ovalshape. A seating seal 230 may aid in the creation of the sealingrelationship by compressing when seating surface 228 and the opposingseating surface 226 are relatively more rigid. Such a seating seal 230may comprise an elastic ring such as a conventional o-ring, and may beoptional in embodiments in which one or both of the seating surface 228or the opposing seating surface 226 have elastic properties, asdescribed more fully below. A piston sealing ring 234 may also create aseal between the body 214 and the piston 220 at a position beyond anoutlet 236 from the flow regulating valve 212, at an end of the flowpassageway 218 opposite to an inlet defined by the seating surface 228.

As described above, the spring 224 provides a spring force which acts tomaintain a seal between the body 214, such as the sloped surface ofseating surface 228, and the opposing seating surface 226, which may befacilitated through use of a seating seal 230. It is of note that theseating seal 230 is not shown compressed in all of the figures to moreclearly illustrate the interface between the opposing seating surface226 and the seating surface 228. Also, in alternate embodiments, ratherthan using or only using a seating seal 230, one or both of the opposingseating surface 226 and the seating surface 228 may be formed with orcomprise an elastic material such as various types of rubber, and thus,either the seating surface may be relatively more elastic than theopposing seating surface or, in additional alternate embodiments, theopposing seating surface may be relatively more elastic than the seatingsurface. Such relationships enable the more rigid of the two surfaces tocompress the more elastic of the two surfaces such that a sealingrelationship exists. For example, a steel piston may compress a rubberbody. Thus, in operation, a first pressurized fluid provided by a firstfluid connection 238 will be sealed against traveling through the flowpassageway 218 when the flow regulating valve 212 remains in a closedposition, as shown in FIG. 2. However, the spring force may be overcomeby opposing forces which displace the piston 220 along the axis 222 in adirection substantially opposite to the direction of the spring force.The opposing forces may be provided by a lever mechanism 240 whichhinges at a hinge point 242. Accordingly, the application of opposingforces substantially opposite to the force provided by the spring 224may enable flow through the flow regulating valve 212, as more fullydescribed below.

In accordance with the above description, the selection of the springwill depend on creating the desired balance between the ability of thespring to seal the flow regulating valve properly and the force requiredto open the flow regulating valve. With further regard to the spring,although various embodiments are shown and described with the springbeing positioned below the piston, the spring could alternatively beplaced on top of the piston such as in the area between the levermechanism 240 and the piston sealing ring 234 or in the area between theseating surface 228 and the piston sealing ring. The importconsideration in this regard is that the spring must bias the seatingsurface 228 against the opposing seating surface 226.

In an alternative embodiment, the valve may unseat in a directionopposite to the flow of the fluid. In such an embodiment, a relativelystronger spring would be required, since the spring would have to workagainst the fluid pressure. However, in such an embodiment the forcerequired to control the flow regulating valve might be more easilymodulated by the user.

The operation of an embodiment of a flow regulating valve 212 will nowbe described in detail with respect to FIGS. 2A-C. As shown in FIG. 2A,the piston 220 is initially biased by a spring force 244 such that theseating surface 228 is in sealing relation with the opposing seatingsurface 226. Thus, no flow of fluid is able to travel through the flowpassageway 218. However, as shown in FIG. 2B, when a first opposingforce 246 is applied to the piston 220 in a direction substantiallyopposite to that of the spring force 244, a small gap 248 may be createdat a location on the perimeter of the piston 220 where the spacing isthe greatest between the seating surface 228 and the opposing seatingsurface 226 which allows for a small fluid flow to travel between theseating surface and the opposing seating surface. Thereafter, the flowtravels through the flow passageway 218 and then out through an outlet236.

Further, as shown in FIG. 2C, when a second opposing force 250, which islarger than the first opposing force 246 (see FIG. 2B), is applied tothe piston 220, in the same direction substantially opposite to that ofthe spring force 244, the sealing relationship between the seatingsurface 228 and the opposing seating surface 226 may be completelyremoved. In such a situation, a large gap 252 is created between theseating surface 228 and the opposing seating surface 226 such that alarge fluid flow may travel through the flow passageway 218 and out theopening 236. Thus, the desired amount of fluid flow through the flowpassageway 218 may be achieved by selecting the force applied to thepiston 220 and against the spring force 244.

One feature in particular enables regulating the flow of fluid. Thisfeature is that of the angle defined between the seating surface 228 andthe opposing seating surface 226. As a result of this angle beingdefined between the seating surface 228 and the opposing seating surface226, a gap (see, e.g. 248, 252) defined between the seating surface andthe opposing seating surface will not be uniform around the perimeter ofthe piston 220 as the seating surface and the opposing seating surfaceunseat. Therefore, a small gap may be created at locations around theperimeter of the piston 220 where the spacing is the greatest betweenthe seating surface 228 and the opposing seating surface 226 whichallows for a small flow of fluid therebetween. However, as additionalforce is applied to the piston 220, the gap may be widened between theseating surface 228 and the opposing seating surface 226 eventually tothe extent that the gap extends around the entire perimeter of thepiston to allow a larger flow of fluid to enter the flow passageway 218.Accordingly, the flow of fluid between the seating surface 228 and theopposing seating surface 226 may be regulated according to how much flowof fluid is desired by selecting the amount of opposite force applied tothe piston.

Although FIGS. 2A-C show a sloped seating surface 228 defined by thebody 214 and an opposing seating surface 226 defined by the piston 220,various other alternative embodiments are available. For example, FIG.2D illustrates an embodiment of a flow regulating valve 212 wherein asloped seating surface 228′ is defined on the piston 220. In thisembodiment, the body 214 may comprise a substantially flat opposingseating surface 226′. Further as shown in FIG. 2E, in some embodimentsthe flow regulating valve 212 may include a first sloped surface ofseating surface 228″ and additionally the opposing seating surface 226″may comprise a second sloped surface.

In embodiments using two sloped surfaces, the piston may be keyed toprevent it from rotating. For example, the piston may comprise anindexing protrusion, which engages a corresponding portion of the bodyof the flow regulating valve. The prevention of rotation keeps the valvein a position that maintains the graduated opening function of thevalve.

However, in alternate embodiments, the body and/or the piston may bekeyed such that the piston can be rotated between a variety ofpositions. This enables a user to change the relative difference in theangle between the first sloped surface and the second sloped surface.For instance, if the first sloped surface and the second sloped surfaceare both of equal angles, then at one position, the two surfaces maycome together without any relative angular difference between the twosurfaces. However, when the piston or body is rotated to a differentposition, there is an angular difference between the two surfaces. Theindexing could provide set positions, such as where there is no relativeangular difference between the first and second sloped surfaces and a180 degree relative rotation of the piston from that position, to makethe valve convertible between a regular valve and a flow regulatingvalve.

Regardless of the particular embodiment and what part or parts of theflow regulating valve comprise a sloped surface or the direction of thesloped surface, an important characteristic, in addition to thedurometer of the sealing surface(s), is the relative angle between theseating surface and the opposing seating surface. In some embodiments,the angle defined between the seating surface and the opposing seatingsurface, may be between 0 and 20°. In particular, in some embodimentsthe angle may be 10°. The angle is of importance, because the angleenables the partial opening of the flow regulating valve. This is incontrast to many known valves, such as Schrader valves, which opensubstantially around the entire perimeter of the valve in anon-graduated manner using two parallel planar surfaces. Accordingly,with such known valves, precise control of the amount of flow travelingthrough the valve is more difficult than with an embodiment of thepresent flow regulating valve of the present invention.

Alternative embodiments of flow regulating valves are also provided,which may or not be provided in a replaceable valve cartridge. FIG. 2Gillustrates a flow regulating valve 2120 designed to regulate the flowof a fluid which may be, for example, water or air. The flow regulatingvalve 2120 comprises a body 2140 which in this embodiment comprises ahead 104 of a dental syringe 100 (see, e.g. FIG. 1A). The body 2140defines a cavity 2170, a portion of which defines a flow passageway2180, through which the fluid may flow when the flow regulating valve2120 is open.

As illustrated in FIG. 2H, a piston 2200, which may be integral with abutton 1030, extends through the cavity 2170 along an axis 2220 havingfirst (e.g. outward) and second (e.g. inward) directions, upon which thepiston axially moves. The piston 2200 may extend through one or morecentering sleeves such as first, second, and third centering sleeves2205, 2206, 2207 which allow axial movement of the piston, butsubstantially restrict other movement. The piston 2200 may also extendthrough a number of seals, such as a flow-control seal 2230, a flowpassageway end seal 2232, and a second flow passageway end seal 2234.The flow passageway 2180 is defined between the flow passageway end seal2232 and the second flow passageway seal 2234. The flow passageway endseal 2232 may be positioned in the second direction from theflow-control seal 2230, and the second passageway end seal 2234 may bepositioned in the first direction from the flow-control seal 2240. Thesleeves 2205, 2206, 2207 and seals 2230, 2232, 2234 may be retained inthe cavity 2170 by a first retaining member which may comprise aretaining pin 2105. The retaining pin 2105 extends at least partiallythrough the body 2140 and restrains movement of the seals 2230, 2232,2234 and sleeves 2205, 2206, 2207 in the first direction along the axis2220 which is generally outward as illustrated in FIG. 2H. In theillustrated embodiment this is accomplished by positioning the retainingpin 2105 such that the third centering sleeve 2207 contacts theretaining pin 2105. Thus, the first centering sleeve 2205, the secondcentering sleeve 2206, and the seals 2230, 2232, 2234 may be preventedfrom moving in the first direction by at least indirectly contacting theretaining pin 2105.

A spring 2240 positioned within a cavity 2210, or other force means, isconfigured to apply a force on the piston 2200 in the first directionalong the axis 2220 tending to push the piston outward. Otherembodiments of force means may include a fluid source, such aspressurized air, configured to supply a fluid force to the piston 2200.The fluid source may be supplied to the cavity 2210. In an alternateembodiment opposing magnetic polarities may be applied to the piston andone or more objects displaced inwardly from the piston in the seconddirection or the body itself Other force means may be used so long asthey are configured to supply a force on the piston 2200 in the firstdirection along the axis 2220 tending to push the piston outward. Thespring 2240 and cavity 2210 (or other force means) may be positionedcoaxially with the piston 2200 and the cavity may thus comprise aportion of the cavity 2170. A second retaining member may couple to thepiston 2200 in the cavity 2210. The second retaining member may comprisean e-clip or c-clip which snaps into a clip groove 2250 (see FIG. 2K″)defined in a portion of the piston 2200 which may positioned in thecavity 2210. In an alternate embodiment, the second retaining membercomprises a nut 2107. When compressed, the spring 2240 applies a forceto the nut 2107 in the first direction, but the movement of the nut andpiston 2200 is at least partially restrained by indirect contact betweenthe nut and the retaining pin 2105. In particular, the nut 2107 maycontact a spacer 2109 which may in turn indirectly contact the retainingpin 2105 through the seals 2230, 2232, 2234 and sleeves 2205, 2206, 2207to restrain movement of the piston 2200 in the first direction. When thesecond retaining member comprises an e-clip or c-clip, the secondretaining member may still operate in substantially the same way.

Regarding operation of the flow regulating valve 2120, when the button1030 is depressed, the piston 2200 moves in the second direction alongthe axis 2220 which is opposite to the first direction, and thusgenerally inward as viewed in FIG. 2H. The seals 2230, 2232, 2234 andsleeves 2205, 2206, 2207, however, are substantially restrained frommovement in the second direction by a lip 2111 defined at the entranceto the cavity 2210, which may be created by forming the cavity of asmaller diameter than the cavity 2170. Thus, when the button 1030 isdepressed, the piston 2200 moves relative to the seals 2230, 2232, 2234and sleeves 2205, 2206, 2207.

This movement controls the flow of fluid through the flow control valve2120. FIG. 2I illustrates a modified perspective view of the flowcontrol valve 2120 to show the flow path to and through the flow controlvalve. Fluid is supplied to the flow control valve 2120 by a fluidsupply conduit 2380 which includes a supply slot 2380′ which is in fluidcommunication with a first portion 2181 of the flow passageway 2180defined between the flow-control seal 2230 and the flow passageway endseal 2232. The fluid supply conduit 2380 may be configured to provide afluid flow applied at the perimeter of the piston 2200. Further, thefluid supply conduit 2380 may in some embodiments be oriented such thatthe pressurized fluid is directed at the piston 2200 substantiallyperpendicularly to the axis of the 2220. Substantially perpendicularherein means any configuration wherein the fluid supply conduit 2380directs the fluid such that is five or more degrees away from parallelwith the axis 2220. Providing a fluid flow applied at the perimeter ofthe piston 2200 in the first portion 2181 of the flow passageway 2180may prevent fluid pressure from producing a force on the piston in thefirst direction such as where a fluid supply is provided from below thepiston axis within the cavity 2210. Such a force may be undesirablebecause it increases the necessary force in the second direction thatthe user must produce to actuate the flow control valve 2120. Inparticular, the user may have to overcome the force produced by thespring 2240 as it is compressed during actuation of the flow controlvalve 2120. Therefore, any additional force in the first direction maymake the flow control valve 2120 more difficult to actuate.

In addition to providing flow applied at the perimeter of the piston2200, the flow control valve 2120 may comprise additional featuresintended to substantially prevent the production of fluid force in thefirst direction. Returning to FIG. 2G, one such feature is that thecavity 2210 may be in communication with a cavity pressure, such asambient air pressure, wherein cavity pressure is less than the pressurein the fluid supply conduit 2380. By allowing the cavity 2210 tocommunicate with ambient air pressure, the force applied to the piston2200 in the second direction will not have to overcome force produced bycompression of fluid within the cavity as the piston moves in the seconddirection. Some embodiments of flow control valves 2120 may include apressure relief conduit 2382, which may comprise a passage in the body2140 leading from the cavity 2210 to the outside of the body tofacilitate communication with ambient air pressure.

Certain embodiments of flow control valves 2120 may additionally oralternatively be configured such that the fluid supply conduit 2380 isout of fluid communication with the distal ends 2200 a, b (see FIG. 2H)of the piston 2200. By keeping the distal ends 2200 a, b of the piston2200 out of fluid communication with the fluid supply conduit 2380, theforce on the piston in the second direction required to operate the flowcontrol valve 2120 may not have to overcome force created by thepressurized fluid in the fluid supply conduit. To prevent the fluidsupply conduit 2380 from communicating with the cavity 2210, and hencethe distal end 2200 b of the piston 2200, the flow passageway end seal2232 may be sized and positioned such that it contacts the piston 2200and the body 2140 to thereby separate the first portion 2181 of the flowpassageway 2180 from the cavity. Additionally or alternatively, the flowcontrol valve 2120 may be configured such that the total area of thepiston 2200 perpendicular to the axis 2220 which is exposed to forcefrom pressurized fluid in the second direction is greater than the totalarea of the piston perpendicular to the axis which is exposed to forcefrom pressurized fluid in the first direction. This may present analternate way to prevent pressurized fluid in the fluid supply conduit2380 from producing a net force in the first direction which a userwould have to overcome when pressing on the button 1030 to operate theflow control valve 2120. In alternate embodiments the total area of thepiston 2200 perpendicular to the axis 2220 which is exposed to forcefrom pressurized fluid in the second direction may be equal to, or less,than the total area of the piston perpendicular to the axis which isexposed to force from pressurized fluid in the first direction. Thesealternate embodiments would produce substantially no net force and aforce in the second direction, which may be desirable in someembodiments.

Returning to description of the operation of the flow control valve2120, when the flow control valve is closed, as illustrated in FIG. 2I,the fluid is at least substantially prevented from flowing from thefirst portion 2181 to a second portion 2182 of the flow passageway 2180,which may be defined between the flow-control seal 2230 and the secondflow passageway end seal 2234. In particular, flow control seal 2230contacts both the body 2140 and the piston 2200 to prevent flow betweenthe first portion 2181 and the second portion 2182 of the flowpassageway 2180. However, when the button 1030 is pressed, the piston2200 translates along the axis 2220 in the second direction (inwardly asillustrated in FIG. 2I), such that the flow control valve 2120 opens. Asillustrated in FIG. 2J, a flow path is thereby created through the flowcontrol valve 2120, which puts the fluid supply conduit 2380 in fluidcommunication with a fluid outlet slot 2381′, which is part of a fluidoutlet conduit 2381, which may supply the fluid to a syringe tip 110(see, e.g. FIG. 1A) positioned within a syringe tip cavity 2160. Thefluid travels from the fluid supply conduit 2380 through the firstportion 2181 of the flow passageway 2180, through the second portion2182 of the flow passageway, and then through the outlet conduit 2381(see FIG. 2J). The flow may be at least partially directed from thesecond portion 2182 of the flow passageway 2180 to the outlet conduit2381 by the second flow passageway end seal 2234, which maysubstantially prevent the fluid from traveling out of the cavity 2170 inthe first direction near the button 1030.

The flow path through the flow passageway 2180 may be more clearly seenin FIG. 2K. When the piston 2200 moves inwardly as a result of the userpushing down on the button 1030 in the second direction (see FIG. 2J)the flow-control seal 2230 may come at least partially out of contactwith the piston at a flow-control groove 2330, or other flow-controlmeans may otherwise allow fluid communication between the first portion2181 and the second portion 2182 of the flow passageway 2180. Thisoccurs, for example, when the flow-control groove 2330 extends at leastpartially beyond the flow-control seal 2230 in both the first and seconddirections. Thereby a flow path is created such that fluid may flow fromthe first portion 2181 of the flow passageway 2180 to the second portion2182 of the flow passageway by traveling between the flow-control seal2230 and the piston 2200 within the flow-control groove 2330. When theuser releases the button 1030, the piston 2200 moves in the firstdirection as a result of the force from the compressed spring 2240,which thereby moves the piston back into sealing contact with theflow-control seal 2230 as the flow-control groove 2330 is displaced fromthe flow-control seal in the first direction. When a second centeringsleeve 2206 is used, the fluid will flow through an inlet aperture 2206a in the second centering sleeve to reach the flow control groove 2330from the fluid supply conduit 2380 (see FIG. 2J). Thereafter, inembodiments comprising a first centering sleeve 2205, the fluid willflow from the flow-control groove 2330 through an outlet aperture 2205 ain the first centering sleeve to reach the fluid outlet conduit 2381(see FIG. 2K′).

Thus, the flow of fluid through the flow control valve 2120 may beallowed or prevented by controlling the position of the piston 2200.However, in some embodiments the flow-control valve 2120 may includefeatures configured to facilitate control of the flow-rate through thevalve. To accomplish this, embodiments of the flow-control groove 2330may comprise a shape such that at least a portion of the piston 2200 atthe flow-control groove defines a plurality of cross-sectionsperpendicular to the axis 2220 of the piston which generally decrease inarea from the farthest portion of the flow-control groove in the seconddirection towards the first direction until a maximum groove depth isreached. In such configurations, the flow-control seal 2230 may breakthe seal with the piston 2200 gradually as the piston is displaced inthe second direction. Thus, one or more small gaps may be createdbetween the piston 2200 and the flow-control seal 2230 at the one ormore flow-control grooves 2330 as the piston is initially displaced inthe second direction. Due to the decreasing cross-sectional area of thepiston 2200 at the flow-control seal 2330, as the piston is furtherdisplaced in the second direction, the one or more gaps between theflow-control seal and the piston increase in size or number. Thus, alarger quantity of fluid may flow through the flow control valve 2120 asthe piston 2200 is displaced further in the second direction.Accordingly, a user may selectively control the flow through the flowcontrol valve 2120 by changing the position of the flow-control groove2330 relative to the flow-control seal 2230 by moving the piston 2200.

Other flow-control means may be used including other embodiments offlow-control grooves that are structural with an alternate shape and/orcross-section linearly along axis 2220 or radially around piston 2200.Also, a flow-control groove may be shaped without a specific intent toassist the control of the flow-rate, such as if the flow-control grooveis a uniform reduced diameter section of the piston 2200. In certainother embodiments the flow-control means may comprise a bore through thepiston 2200, the bore comprising at least first and second apertureswhich are displaced along the axis 2220. Regardless of the particularembodiment of the flow-control means, it will be configured such thatthe first portion 2181 of the flow passageway 2180 is not in fluidcommunication with the second portion 2182 of the flow passageway whenthe piston 2200 is in the first position, but is in fluid communicationwith the second portion of the flow passageway when the piston is in thesecond position. The various embodiments of flow-control means may ormay not have characteristics intended to assist in controlling the fluidflow-rate. For example, the flow-control means may be configured topermit increasing flow of fluid through the valve as the piston isdisplaced in the second direction.

FIGS. 2K″-2K′″″ illustrate one embodiment of a piston 2200 withflow-control grooves 2330. As illustrated, the piston 2200 may comprisea plurality of flow control grooves 2330. As discussed above, the flowrate through the valve may be adjusted in a number of ways. Inparticular, the number of flow-control grooves 2330 may be changed. Thepiston 2200 may comprise various numbers of flow-control grooves 2330,such as 2, 4, or 6, although other numbers of flow-control grooves maybe used. As may be seen in FIG. 2K′″, which is an enlarged portion ofthe cross-section of the piston 2200 from FIG. 2K″, each flow-controlgroove 2330 may taper in depth, as described above. Each flow controlgroove 2330 may taper in depth along a length 2252 and/or across a width2254 as respectively illustrated in FIGS. 2K″″ and 2K′″″. Such featuresmay adjusted to control the flow rate through the flow control valve2120.

Flow control may additionally or alternatively be accomplished by usinga metering screw 3000, which may comprise a portion of the fluid supplyconduit 2380 as illustrated in FIG. 2L. In particular, the meteringscrew 3000 may be positioned within a body 2140 such as a head portion3104 of a dental syringe. However, the metering screw may be used invarious other positions and embodiments wherein it may be desirable tocontrol the flow of a fluid. It should be noted that the metering screw3000 and the flow control valve 2120 affect flow in different ways, andhence they may be used in combination. In this regard, the meteringscrew 3000 generally controls the maximum fluid flow rate through adental syringe. In comparison, the flow control valve 2120 controls thereal-time metering of fluid out of the tip of the dental syringe, up tothe maximum flow rate as defined by the metering screw. Thus, the flowcontrol valve 2120 and metering screw may work in conjunction to providethe desired operation of the dental syringe.

As illustrated in FIG. 2L, the metering screw 3000 may comprise acylindrical end portion 3002 having a first diameter which is configuredto be received by a metering cavity 3012 in the body 2140. The meteringcavity 3012 comprises a cylindrical end cavity 3012 a having a seconddiameter which is greater than the first diameter defined by thecylindrical end portion 3002. The cylindrical end portion 3002 ismoveable from an extended position (FIG. 2L) to a retracted position(FIG. 2N). When the cylindrical end portion 3002 is in the extendedposition, the metering screw 3000 occupies a first volume of themetering cavity 3012, and when the cylindrical end portion is in theretracted position, the metering screw occupies a second volume of themetering cavity, wherein the second volume is less than the firstvolume. Thus, when the metering screw 3000 is in the extended position,a relatively small flow 3100 is allowed to travel around the meteringscrew through the fluid supply conduit 2380 (FIG. 2L), whereas when themetering screw is in the retracted position, a relatively large flow3100′ is allowed to travel around and past the metering screw (FIG. 2N).

The metering screw 3000 may comprise a threaded portion 3004 configuredto screw into a threaded receiving portion 3006 of the metering cavity3012. The metering screw 3000 may further comprise a cutout portion 3008configured to receive the tip of a screwdriver or a similar tool. Thus,by inserting the tip of a screwdriver, for example, in the cutoutportion 3008, the metering screw 3000 may be rotated to retract orextend the metering screw. In so doing, the movement of the threadedportion 3004 of the metering screw 3000 with respect to the threadedreceiving portion 3006 of the metering cavity 3012 causes axialtranslation of the metering screw such that it retracts from or extendsinto the metering cavity 3012. In alternate embodiments, the meteringscrew may comprise a handle, lever, or other device which may allow themetering screw to be adjusted without requiring a separate tool.Regardless of the particular adjustment mechanism used, leakage of fluidout of the metering cavity 3012 between the threaded portion 3004 of themetering screw 3000 and the threaded receiving portion 3006 of themetering cavity may be prevented by a seal 3020, which may comprise ano-ring seal. The seal 3020 may contact both the metering screw 3000 andthe metering cavity 3012 to thereby prevent flow out of the meteringcavity past the threaded portion 3004 of the metering screw.

The metering screw 3000 may be configured such that the fluid supplyconduit 2380 is in fluid communication with the first portion of theflow passageway 2181 (see FIG. 2J) regardless of whether the cylindricalend portion 3002 is in the extended position (FIG. 2L) or the retractedposition (FIG. 2N). This is due to the first diameter of the cylindricalend portion 3002 being less than the second diameter of the cylindricalend cavity 3012 a as described above. As a result of the difference indiameters, in the extended position a relatively small fluid flow 3100may pass by the metering screw by flowing around the cylindrical endportion 3002 of the metering screw 3000 in the gap between the firstdiameter and the second diameter.

Because in some embodiments both the head portion 3104 of a dentalsyringe and the metering screw 3000 may be formed from metal or otherincompressible materials, the head portion and the metering screw maynot form a perfect seal against one another. Therefore, an alternateembodiment of a metering screw 3000′ and corresponding fluid flowmetering system are also provided. As illustrated in FIGS. 2M and 2O, acylindrical end portion 3002′ of the metering screw 3000′ may comprise acompressible material, which may be elastomeric, such that when themetering screw is extended into the cavity 3012, the cylindrical endportion 3002′ may be compressed along the longitudinal axis of themetering screw, which may cause a radial expansion of the cylindricalend portion such that it would cause the cylindrical end portion tosubstantially entirely seal against the metering cavity 3012, so thatflow is substantially entirely blocked. Further, as a result of formingthe cylindrical end portion 3002′ from a compressible material, use ofan o-ring (e.g. o-seal 3020) may not be required because the cylindricalend may be dimensioned such that it sealingly contacts the body 2140 andthereby substantially prevents flow of fluid out of the metering cavity3012 past a threaded portion 3004′ of the metering screw. Similarly tothe previously discussed embodiments, the metering screw 3002′ may bemoved to a retracted position wherein the compressible cylindrical endportion 3002′ of the metering screw 3000′ is at least partially out ofcontact with the cylindrical end portion to allow flow of the fluidtherethrough.

The metering screw 3000′ may include a threaded portion 3004′ defining afirst end rotatably operable by a user such as through use of the cutoutportion 3008′ defined in the first end. The threaded portion 3004′ mayalso define a second end defining a cavity 3004 a′ which receives thecompressible cylindrical end portion 3002′ which extends therefrom alongan axis. The cylindrical end portion 3002′ may include a spherical end3002 a′ which is configured to engage a corresponding spherical end3011′ of the metering cavity 3012. In some embodiments, the threadedportion 3004′ of the metering screw 3000′ may be formed from a differentmaterial than the cylindrical end portion 3002′ of the metering screw.For example, the threaded portion 3004′ may be formed from a metal orother substantially rigid material which facilitates use of the cutoutportion 3008′ when adjusting the metering screw 3000′ by screwing it inor out.

Returning to the replaceable valve cartridge, FIG. 3 illustrates anembodiment of a replaceable valve cartridge 306 separate fromcorresponding head and handle portions of a dental syringe. Thereplaceable valve cartridge 306 may comprise a housing 356 having one ormore indexing protrusions 358. As shown in FIG. 3A, the indexingprotrusions 358 may engage corresponding indentions 360 in the headportion 304 of a dental syringe 100. As previously described, thereplaceable valve cartridge 306 may include one or more flow-regulatingvalves 212, which may be substantially enclosed within the housing 356.Accordingly, FIGS. 3 and 3A-3C illustrate embodiments of a replaceablevalve cartridge 306 configured to include one or more pistons 320extending from the housing 356. These pistons 320 may be engaged bylevers 340 to operate the flow regulating valves 212.

With reference to FIG. 3A, one or more buttons 303 are movably operableto engage the levers 340 to actuate the pistons 320 and thereby operatethe valves 212. Referring to FIG. 3B, the housing 356 may comprise threecavities 362′, 362″, and 362′″. Each cavity 362′, 362″, and 362′″ mayhouse a corresponding valve mechanism. For example, a first cavity 362′may house a flow regulating valve 212 controlling the flow of airthrough the replaceable valve cartridge 306. Also, a second cavity 362″may house a flow regulating valve 212 controlling the flow of waterthrough the replaceable valve cartridge 306. The third cavity 362′″ inthe housing 356 of the replaceable valve cartridge 306 may house asystem to remove a residual liquid from a tip of the dental syringe, aswill be described in detail below.

Referring to FIG. 3A, it was previously noted that the indexingprotrusions 358 align the replaceable valve cartridge 306 with the headportion 304 of a dental syringe. Further, as shown in FIGS. 3 and 3A,the replaceable valve cartridge 306 may comprise a seating shoulderportion 364 which engages a corresponding inside surface of the headportion 304 of a dental syringe when the replaceable valve cartridge isfully inserted within the head portion. Accordingly, proper alignmentand insertion depth of the replaceable valve cartridge 306 within thehead portion 304 may be achieved with relative ease. Referring now toFIG. 3C, the replaceable valve cartridge 306 may further comprise a seal366 for sealing an axially inserted dental syringe tip. The seal 366 forsealing an axially inserted dental syringe tip, which will be describedin greater detail below, may allow fluid which escapes past the seal tobe in communication with a bleed path 368 (see FIG. 3B) out of thehousing 356 of the replaceable valve cartridge 306. Once the fluidescapes out of the bleed path 368, the fluid could potentially fill thehead portion 304 (see FIG. 3A). To avoid this, and to allow the user ofthe dental syringe to know when the seal 366 is leaking, the replaceablevalve cartridge may further include a notch 369, which allows the fluidescaping past the seal and through the bleed path 368 to travel throughthe notch and out of the bottom of the dental syringe. Thus, the user ofthe dental syringe may be able recognize that the seal 366 is notworking properly.

With regard to the positioning of the levers 340, as shown in FIG. 3C,each may be positioned on opposing sides of the seal 366 for sealing anaxially inserted dental syringe tip. Further, when the replaceable valvecartridge 306 is inserted into the head portion 304 of the dentalsyringe, the seal 366 for sealing an axially inserted dental syringe tipmay be configured to align with an aperture 370 (see FIG. 3A) in thehead portion. Such a configuration allows for axial insertion of adental syringe tip along a longitudinal axis of the seal 366 for sealingan axially inserted dental syringe tip.

Returning to the cavities 362′, 362″, and 362′″ in the housing 356 whichmay house valves, one or more of the cavities may include a fluidconnection 372′, 372″, such as shown in FIG. 3 or FIG. 3A. For example,the first cavity 362′ may be in fluid communication with a firstconnection 372′ and the second cavity 362″ may be in fluid communicationwith a second fluid connection 372″. Additionally, a third valvemechanism, such as a system to remove a residual liquid from the tip ofa dental syringe, may be in fluid communication with the first fluidconnection 372′, as will be discussed later. In such an embodiment thefirst fluid may comprise a gas such as air.

Thus, the above described replaceable valve cartridge houses many of themoving parts in a dental syringe in a single replaceable valvecartridge. Accordingly, operation and maintenance of a dental syringemay be substantially simplified, particularly in light of the ability ofthe dental syringe to separate into a head portion and a handle portionand allow for easy insertion and removal of the replaceable valvecartridge. Thus, a dental assistant may be able to replace thereplaceable valve cartridge with relative ease. In comparison, manyprior art dental syringes require special tools and expertise to takeapart the dental syringes, and hence many prior art dental syringes maynot be fully serviceable by dental assistants.

FIGS. 4 and 4A-4I illustrate additional features of embodiments of thedental syringe. The head portion 404 of the dental syringe may comprisea tip retention insert 408 as shown in FIG. 4. As shown in FIG. 4A, thetip retention insert 408 may comprise a housing at least partiallydefining a cavity 474 configured for insertion of a dental syringe tip.As shown in FIG. 4B, such a cavity 474 may align with an aperture 476 inthe head portion 404 of the dental syringe which together enableinsertion of a dental syringe tip.

As shown in FIGS. 4A and 4B, the tip retention insert 408 may furthercomprise one or more releasable cartridge retentioners 478. Thereleasable cartridge retentioners 478 may be configured to releasablyhold the tip retention insert 408 in a head portion 404 of a dentalsyringe by engaging corresponding cavities 479. The releasable cartridgeretentioners 478 may be released by breaking the interference fit formedby the releasable cartridge retentioners and corresponding cavities 479in the head portion 404, such as through inserting relatively thin andflat objects between the releasable cartridge retentioners and thecorresponding cavities. For example, a flat head screw driver having avery thin head may be able to remove the tip retention insert 408.Alternatively, the tip retention insert 408 may be removed in someembodiments by applying sufficient pressure on one side of the tipretention insert to overcome the retention force and push the insert outof the side of the head portion 404. Accordingly, the tip retentioninsert 408 may be replaceable from the head portion 404 of a dentalsyringe in certain embodiments.

In general, the tip retention insert 408 may comprise one or moreclamping members movably positioned around the cavity 474. As shown inthe embodiment of FIG. 4A, the clamping members may comprise a firstplate 480′ and a second plate 480″. Embodiments of the tip retentioninsert 408 may further generally comprise one or more springs configuredto bias the clamping members at least partially into the cavity 474. Asshown in the embodiment of FIGS. 4C-4E, the springs can be coil springs482. The embodiments of the tip retention insert 408 shown in FIGS.4C-4E further include a plurality of buttons 484 configured to move bothplates 480′, 480″ against the force of the spring 482. In particular, inthe illustrated embodiments, each plate 480′, 480″ is fixed to acorresponding button. As may be apparent to one of ordinary skill in theart, in alternate embodiments, a single button may be configured to moveone plate against the force of a spring to release and secure a dentalsyringe tip. Such a button could alternatively extend from the top ofthe head portion of the dental syringe instead of a side.

FIG. 4F illustrates an embodiment of the first plate 480′ and FIG. 4Gillustrates an embodiment of the second plate 480″ from FIGS. 4A-4E. Asshown in FIG. 4C, when the two buttons 484 are displaced inwardlytowards one another, the cavity 474 comprises a relatively large areaallowing for axial insertion of a dental syringe tip 410 because theplates 480′, 480″ slide into such a position that rounded larger opensections 485′, 485″of the plates overlap. However, as the buttons 484are released, the two plates 480′, 480″ move to such a position thatangled locking sections 487′, 487″ overlap to form a relatively smallercavity 474, which may lock onto a dental syringe tip 410 to provide asecure interlocking connection, as shown in FIGS. 4D and 4E.

In various embodiments, the tip retention insert 408 may lock ontodifferent shapes of dental syringe tips 410. Depending on the particulardental syringe tip 410 which is being engaged, the plates may takedifferent forms. In particular, when in a locked configuration such asshown in FIGS. 4D and 4E, the angled locking sections 487′, 487″ of thetwo plates 480′, 480″ may combine to form a cavity 474 in the shape of apentagon or in alternative embodiments the cavity may take the form of ahexagon. For example, when a dental syringe tip is shaped like ahexagon, the angled locking sections of the plates may preferably alsoform a hexagon so that the angled locking sections may engage all sixsides of the dental syringe tip and thereby help to prevent rotation ofthe dental syringe tip. As will be apparent to one of ordinary skill inthe art, various other cavity shapes may be usable depending on theshape of the particular dental syringe tip being inserted into thedental syringe. An important consideration in this regard is the shapeof the cavity formed by the angled locking sections of the two plateswhen they are in the locked position. The shape of the cavity formed bythe rounded larger open sections of the two plates when the two platesare in an unlocked position may take many different forms so long as thecavity is large enough to allow for insertion of the dental syringe tip.

FIGS. 4H-4J illustrate an alternate embodiment of a tip retention insert408′. In this embodiment, the tip retention insert 408′ is configured tohold both regular (non-indexing) and indexing syringe tips 410. FIG. 4Hillustrates the tip retention insert 408′ in an open position whichallows for the insertion of a dental syringe tip 410 due to the twobuttons 484′ being displaced inwardly towards one another, as describedin the embodiment of FIGS. 4C-4G. When the buttons 484′ are depressed,two rounded larger open sections 483′, 483″ of two plates 481′, 481″,which may be substantially similar to one another but oriented inopposite directions, combine to form a large cavity 474′ which allowsfor insertion of the dental syringe tip 410.

FIG. 4I illustrates the embodiment of the tip retention insert 408′ ofFIG. 4H in which the two buttons 484′ have been released and hence thetwo plates 481′, 481″ clamp against the dental syringe tip 410, which inthis figure comprises a regular (non-indexing tip). Accordingly,intermediate locking sections 489′, 489″ form a smaller cavity 474′ andengage the dental syringe tip 410 in order to hold it in place. Theintermediate locking sections 489′, 489″ may combine to form a radiusthat is slightly smaller than that of the dental syringe tip 410, suchthat the dental syringe tip may be securely engaged.

FIG. 4J also illustrates the embodiment of the tip retention insert 408′of FIG. 4H. However, in this embodiment, the tip retention insert 408′is illustrated as locking onto an indexing dental syringe tip 410. Insuch an embodiment, distal locking sections 491′, 491″ engage the dentalsyringe tip 410. The distal locking sections 491′, 491″ form a cavity474′ with a cross-section that is smaller than the cross-section formedby the intermediate locking sections 489′, 489″ (see FIG. 4I). Thus,indexing syringe tips 410 having a number of opposing flat sections 493,e.g. 2, 4, 6, 8, etc., may be locked in place by the distal lockingsections 491′, 491″ of the tip retention mechanism 408′. Accordingly,the embodiment of a tip retention insert 408′ illustrated in FIGS. 4H-4Jmay hold both indexing and regular dental syringe tips 410.

FIGS. 4K and 4L illustrate an alternate embodiment of the tip retentioninsert 408″. In this embodiment, the clamping members may comprise aplurality of ball bearings 486 wherein one or more springs provide aradially inwardly directed force on each of the ball bearings. In suchan embodiment the spring may comprise a torsion spring 488′, 488″. Suchan embodiment of the tip retention insert 408″ may further comprise aplurality of spacer elements 490′, 490″ positioned between the ballbearings 486 and configured to hold each of the ball bearings in arespective channel 492. As in the case with the previously describedembodiments of tip retention inserts, one or more buttons 484″ may beused to release a syringe tip 410. In particular, in this embodimentwhen the one or more buttons 484″ are compressed, the radially inwardlydirected spring force on the ball bearings 486 is reduced as thediameter of the torsion spring 488′, 488″ enlarges and hence axialinsertion or removal of a dental syringe tip 410 is enabled. This allowsfor quick and easy dental syringe tip insertion and removal. Incomparison, some prior art dental syringes require tools and morecumbersome procedures to replace dental syringe tips.

When one or more buttons 484″ are released, the spring tension returnsto the ball bearings 486 as the diameter of the torsion spring 488′,488″ reduces and hence the ball bearings 486 compress upon the dentalsyringe tip 410 from various radial directions to hold the dentalsyringe tip in place. As is the case with previously describedembodiments of the tip retention insert, the number and type of clampingmembers may be selected to prevent rotation of the dental syringe tip.Further, the number and type of clamping members may be selected toprovide an indexing function. Indexing and prevention of rotation of thedental syringe tip may be preferable in certain applications because itis known to use a dental syringe tip to engage the inside of a cheek ofthe mouth and push or pull the cheek during certain oral procedures, andhence a rotationally fixed dental syringe tip is preferable in certainapplications.

The cross-section illustrated in FIG. 4K and the modified cross-sectionillustrated in FIG. 4L show how the spring 488″ connects to both of thebuttons 484″. However, as will be apparent to one of ordinary skill inthe art, alternate embodiments may use a spring connecting to a singlebutton. Further, as shown in both of the embodiments of FIGS. 4K and 4L,the buttons 484″ may be hingedly connected to the rest of the tipretention insert 408″. As will be apparent to one of ordinary skill inthe art, various other mechanisms allowing for compression of the springmay be used, such as simple lever mechanisms. Alternatively, twoopposing plates could slide inwardly to apply force radially inwardly onthe plurality of balls in place of the torsion springs.

Referring now to FIG. 5, a dental syringe may comprise a bleed-overprevention manifold for sealing an axially inserted dental syringe tip,such as included in a replaceable valve cartridge. Embodiments of such ableed-over prevention manifold may be configured to direct a first fluidthrough a first fluid path, direct a second fluid through a second fluidpath, prevent bleed-over of the first fluid into the second fluid pathand prevent bleed-over of the second fluid into the first fluid path, aswill be described below. Thus, as shown in FIG. 5, a bleed-overprevention manifold 594 may comprise a first channel 596 defined betweena first ring 598 of a first elastic portion and a second ring 5100 of asecond elastic portion. As will be described below, the first channel596 may define a low pressure zone configured to permit any of a firstfluid and a second fluid which reaches the first channel to exit througha bleed path. One embodiment of a bleed path is shown in FIG. 5A. Insuch an embodiment, the bleed path 5102 comprises a hole in the housing556 of the replaceable valve cartridge 506 in which the bleed-overprevention manifold 594 is inserted.

Referring to FIG. 5, the bleed-over prevention manifold 594 may furthercomprise a second channel 5104. FIG. 5B illustrates an embodiment of ableed-over prevention manifold 594 in which the second channel 5104 isin fluid communication with the first channel 596. Such fluidcommunication can occur through, for example, one or more holes 5106extending through the bleed-over prevention manifold 594 which link thefirst channel 596 and second channel 5104. With further regard to thefirst channel 596, the first channel may be defined by a first outersurface 5108 of the first ring 598 and a second outer surface 5110 ofthe second ring 5100. Also, as may be seen in FIG. 5, the second channel5104 may be defined by a first inner surface 5112 of the first ring 598and a second inner surface 5114 of the second ring 5100.

In the embodiments shown in FIGS. 5, 5A and 5B, the first ring 598 andthe second ring 5100 are parts of a unitary body. However, in alternateembodiments, such as the embodiment of a bleed-over prevention manifold594′ shown in FIG. 5C, the first ring 598′ and the second ring 5100′ maydefine separate structures, such as a pair of separate o-ringssandwiched together. Regardless of whether the first ring and the secondring are unitary, however, the function of guiding fluids along theirrespective paths into the dental syringe tip and preventing bleed-overis the same. Referring to FIG. 5, a first fluid 5114 such as air travelsalong a first fluid path through a valve, such as a replaceable valvecartridge and enters an outer circumferential channel 5116 definedwithin the dental syringe tip 510 through one or more orifices 5115 inthe dental syringe tip. When the bleed-over prevention manifold 594comprises a unitary body, this may occur through one or more holes 5117in the bleed-over prevention manifold. In such an embodiment, thebleed-over prevention manifold may comprise an annular support ring 5119which strengthens the bleed-over prevention manifold 594 so as toprevent the bleed-over prevention manifold from collapsing under thepressure of the first fluid 5114. As may be seen in FIG. 5A, the annularsupport ring 5119 may actually be segmented such that fluid may moreeasily reach the holes 5117 in the bleed-over prevention manifold 594.Further, a second fluid 5118 such as water travels along a second fluidpath and enters through an end 5111 of the dental syringe tip 510 andthen moves through a centrally defined channel 5120 within the dentalsyringe tip. In such a configuration, the potential exists for eitherthe first fluid 5114 to bleed-over and enter the inner channel 5120 orthe second fluid 5118 to bleed-over and enter the outer channel 5116.The mixing of fluids within a dental syringe tip can be problematic incertain applications making use of a dental syringe such as dentalprocedures where an adhesive is being used which may fail to adhereproperly when exposed to water. For example, water may leak into theouter channel 5116 and come out of the dental syringe when only air issupposed to be dispensed. Accordingly, the bleed-over preventionmanifold 594 is designed to prevent bleed-over into the dental syringetip 510.

Referring to FIG. 5C, the first channel 596′ permits any of a firstfluid 5114′ and a second fluid 5118′ which reach the first channel toexit through the bleed path 5102′. This is due to the first channel 596′defining a relatively low pressure zone because the first channel is influid communication with the bleed path 5102′ which leads to ambientpressure, in comparison to the surrounding areas which are exposed tothe pressurized first fluid 5114′ and second fluid 5118′. Accordingly,any of either the first fluid 5114′ or the second fluid 5118′ whichpasses respective ones of the first ring 598′ or the second ring 5100′or otherwise enters the first channel 596′ is permitted to exit throughthe bleed path 5102′, rather than mix within the dental syringe tip 510.In embodiments in which there is a second channel 5104, such as theembodiment of FIG. 5B, any such leaking first fluid 5114 or second fluid5118 may travel from the second channel through one or more holes 5106to the first channel 596 before exiting the bleed-over preventionmanifold 594, as described above. Any such leakage may occur due toleakage past the rings, as described above. Or, the leakage may occurdue to a tear in a seal, as, for example, resulting from a seal beingcut by syringe tip that has had its end damaged, or which has a burr ofmetal material on it.

Referring now to FIG. 6, a dental syringe may comprise a system toremove a residual liquid from a tip of a dental syringe, such asincluded in a replaceable valve cartridge. This system may be usefulafter a dental syringe dispenses water, and thereafter a drop of waterremains on the tip of the dental syringe. As described above, the mixingof fluids within a dental syringe tip can be problematic in certainapplications making use of a dental syringe such as procedures where anadhesive is being used which may fail to adhere properly when exposed towater. Thus, an embodiment of a system and an apparatus to remove aresidual liquid from a tip of a dental syringe will first be described,followed by embodiments of corresponding methods. FIGS. 6A-6C illustratean embodiment of a system 6122 to remove residual liquid from a tip of adental syringe having supplies of a liquid and the second fluid thereto.In the illustrated embodiment, a body 656 defines a cavity 662′″comprising an inlet 6126, an outlet 6128, an outlet sealing surface6130. The body 656 may comprise the housing of the previously describedreplaceable valve cartridge when the system 6122 is part of areplaceable valve cartridge. A movable stopper 6132 may be locatedwithin the cavity 662′″ and may be configured to be sealable against theoutlet sealing surface 6130. Further, a plunger 6134 may be configuredto be able to move in a first direction along a longitudinal axis of theplunger against the force of a spring 6136 to at least partially enterthe cavity 662′″, such as through the outlet 6128 and contact themoveable stopper 6132. The plunger 6134 may be further configured to beable to move in a second direction under the force of the spring 6136,substantially opposite to the first direction such that a flow path isformed through the inlet 6126, the cavity 662′″, the outlet 6128, and anoutlet channel 6137 in fluid communication with the tip of a dentalsyringe.

FIGS. 6A-6C illustrate the operation of the system 6122 to removeresidual fluid, typically a liquid such as water, from a tip of a dentalsyringe. FIG. 6A illustrates an embodiment of the system 6122 in which apressurized second fluid 6114, typically a gas such as air, is suppliedto the dental syringe but no water is presently being dispensed from thedental syringe. As illustrated within this embodiment, the cavity 662′″enclosing a movable stopper 6132 may be in fluid communication with asecond cavity 662′ connected to the pressurized air 6114. Such fluidcommunication may occur through a channel 6138. Further, the secondcavity 662′ may comprise a flow regulating valve 612 controlling theflow of the air 6114. Thus, as shown, the pressurized supply of air 6114forces the movable stopper 6132 against the outlet sealing surface 6130so as to at least partially seal the outlet 6128.

As shown in FIG. 6B, as the plunger 6134 is displaced in a firstdirection along the longitudinal axis of the plunger such as byactuation of a lever 640, which may also operate a valve controllingdispensing of the water to the tip of a dental syringe, the plungerdisplaces the moveable stopper 6132 from the outlet sealing surface6130. Depending upon the orientation of the cavity 662′″ with respect toa vertical direction, the movable stopper 6132 may travel in the firstdirection to the opposite end of the cavity under the force of gravitywhere the moveable stopper may come to rest on the inlet surface 6140.

Referring now to FIG. 6C, when the plunger 6134 returns in a seconddirection substantially opposite to the first direction as the lever 640is released and hence the water supply to the tip of the dental syringeceases, the pressure from the air 6114 forces the plunger to move beyondits original resting position to a position which is displaced in thesecond direction. In such a position, the plunger 6134 separates fromsurrounding structure to create an opening 6142 which is in fluidcommunication with the dental syringe tip through the outlet channel6137. Thus, a puff of the air 6114 may travel through the inlet 6126,into the cavity 662″, around the movable stopper 6132, out the outlet6128 and opening 6142, and through the outlet channel 6137 to the dentalsyringe tip to remove residual water at the end of the dental syringetip. The air 6114 is able to pass the movable stopper 6132 because themoveable stopper has dimensions relatively smaller than that of thecavity 662′″. In particular, in some embodiments, the cavity 662′″ maybe substantially cylindrical and define a cavity radius. In suchembodiments, the moveable stopper 6132 may define a stopper radiuswherein the stopper radius is smaller than the cavity radius, but largeenough so that the air 6114 pressure creates a seal.

The relative dimensions between the movable stopper 6132 and the cavity662′″ may at least partially determine the length of time during whichthe air 6114 flows out of the outlet 6130 and opening 6142 before themovable stopper is returned to the first position as shown in FIG. 6A atwhich the moveable stopper rests against the outlet sealing surface6130. In particular, a tighter fit between the moveable stopper 6132 andthe cavity 662′″ may cause the moveable stopper to move rapidly underthe force of the pressurized air 6114 as there would be less room forthe air 6114 to move past the moveable stopper than if not a tight fit.A tight fit refers to one in which the radius of the moveable stopper6132 is close to that of the cavity 662′″. Once the movable stopper 6132returns to the outlet sealing surface 6130, the plunger 6134 alsoreturns to an unbiased position as shown in FIG. 6A. As described above,in certain embodiments, the plunger 6134 may be configured to beactuated by a lever 640 that also actuates a water supply to the tip ofthe dental syringe. Thus, a puff of the air 6114 may automatically occurafter each time the valve in fluid communication with the water supplydispenses a flow of water. Accordingly, as described above, this mayremove any residual water from the tip of a dental syringe, which may bebeneficial during certain dental procedures.

The system 6122 to remove residual water from the tip of a dentalsyringe may further comprise an outlet spring 6133 which is configuredto bias the moveable stopper 6132 away from the outlet sealing surface6130. For example, the outlet spring 6133 could comprise a coil springwhich extends from the outlet sealing surface 6130 toward the moveablestopper 6132. The outlet spring 6133 may assist in the operation of thesystem 6122 when operating in positions where the system is tiltedbeyond horizontal by applying a small force on the moveable stopper 6132which is strong enough to bias the moveable stopper away from the outletsealing surface 6130, but which is not strong enough to bias themoveable stopper away from the outlet sealing surface when the air 6114applies pressure to the moveable stopper. Accordingly, as describedabove, the outlet spring 6133 may enable a puff of air 6114 to travelpast the moveable stopper 6132 even when the system is oriented suchthat gravity pulls the moveable stopper in the second direction towardthe outlet sealing surface 6130 because the outlet 6128 may remain atleast partially open due to the outlet spring biasing the moveablestopper away from the outlet sealing surface.

FIG. 6D illustrates an additional embodiment of a system 6122 a toremove residual water from the tip of a dental syringe. This system 6122a is substantially similar to the above-described system 6122illustrated in FIGS. 6A-C with small differences as will be described.The system 6122 a may comprise a plunger 6134 a which is configured todisplace a moveable stopper 6132 a from an outlet sealing surface 6130a. A pressurized supply of air 6114 a forces the movable stopper 6132 aagainst an outlet sealing surface 6130 a so as to at least partiallyseal the outlet 6128 a. When the plunger 6134 a is depressed, itcontacts the moveable stopper 6132 a and thereby displaces the moveablestopper 6132 a from the outlet sealing surface 6130 a and equalizespressure on the stopper in all directions, as in the previouslydescribed embodiment. At the same time, water travels through the system6122 a from an inlet 6980 a to an outlet 6982 a and to a syringe tip aspreviously described. However, when the plunger 6134 a is released, anopening 6142 a allows the pressurized supply of air 6114 a to flowthrough the cavity 662 a′ in which the moveable stopper 6132 a islocated to an outlet channel 6137 a to thereby remove any residual waterfrom the tip of the dental syringe. In some embodiments the opening 6142a may comprise one or more holes through the plunger 6134 a which do notallow for fluid communication between the cavity 662 a′″ and the outletchannel 6137 a when the plunger is depressed (due to the opening beingentirely below a seal 6184 a), but which do allow for fluidcommunication after the plunger is released (due to the opening defininga flow path past the seal) until the moveable stopper 6132 a returns tothe outlet sealing surface 6130 a. Accordingly, embodiments of adifferent system 6122 a for removing liquid from the tip of a dentalsyringe are also provided.

Although the above-described system may remove residual water from a tipof a dental syringe, other systems and apparatuses may be used for thesame function. Accordingly, as shown in FIG. 7A, a method of removing aresidual liquid from a tip of a dental syringe having supplies of aliquid and a second fluid thereto, is provided. The method may compriseactuating a single actuator as shown above at block 7144 to dispense aliquid from a tip of the dental syringe as shown at block 7146.Actuating the single actuator may further automatically dispense thesecond fluid out of the tip of the dental syringe following thedispensing of the liquid as shown at block 7148. Accordingly, the secondfluid substantially removes the residual liquid from the tip of thedental syringe as shown at block 7150. In certain embodiments the liquidmay comprise water as shown at block 7152 and the second fluid maycomprise air as shown at block 7154. As previously described, water andair are often used in dental syringes. Further, as also previouslydescribed, accidental application of water during certain dentalprocedures can be detrimental and therefore use of air to removeresidual water can be beneficial.

Automatically dispensing the second fluid out of the tip of the dentalsyringe following the dispensing of the liquid may further comprisedispensing a controlled quantity of the fluid 7156. Additionally, thestep of automatically dispensing the second fluid out of the tip of thedental syringe following the dispensing of the liquid may furthercomprise dispensing the second fluid for a controlled period of time7158. Accordingly, a desired quantity of the second fluid may bedispensed, or a desired duration of dispensing of the second fluid maybe obtained. For example, with regard to the system 6122 discussed inFIGS. 6A-6C, the relative dimensions of the movable stopper 6132 and thecavity 662′″ may have an effect on both of these factors, with closerrelative dimensions resulting in shorter durations and smallerquantities of the second fluid. Therefore, controlled quantities anddurations of dispensing of the second fluid may be obtained, forexample, by empirical testing using different dimensions for themoveable stopper 6132 and the cavity 662′″.

An additional method and system for removing residual water from a tipof a dental syringe having supplies of water and air thereto is providedin FIG. 7B. The system may comprise a controller 7176 in communicationwith a water sensor 7178 and an air sensor 7184. The water sensor 7178may be in communication with a water valve 7180, which controls thedispensing of water from a water source 7182. Similarly, the air sensor7184 may be in communication with an air valve 7186, which controls thedispensing of air from an air source 7188.

The method associated with the above described system may operate asfollows. The method may involve starting, as shown at block 7160,followed by waiting for the water to flow, as shown at block 7162. Themethod may further comprise checking whether the water is flowing, asshown at block 7164. If the water is not flowing, the method may returnto waiting for the water to flow, as shown at block 7162. If the wateris flowing, the method may further comprise waiting for the water tostop flowing, as shown at block 7166, and checking whether the water hasstopped flowing, as shown at block 7168. If the water has not stoppedflowing, the method may return to waiting for the water to stop flowing,as shown at block 7166. If the water has stopped flowing, the method mayfurther include flowing air, as shown at block 7170. Whether or not thewater is flowing or has stopped flowing may be determined, for example,using the water sensor 7178.

The above flow of air may remove residual water from a tip of a dentalsyringe, as described previously. Additionally, the method may furthercomprise determining whether the water has flowed for a desiredduration, as shown at block 7172, or additionally or alternatively,determining whether the desired quantity of air has flowed, as shown atblock 7174. The signal from the air sensor 7184 may be used to makethese determinations. The entire method may return to the start, asshown at block 7180, if either or both of the desired duration orquantity of air flow has been achieved. While the above description of amethod has referenced particular system components, one of ordinaryskill in the art would understand that various other electrical and ormechanical components may be used. Further, while the above system andmethod are described in terms of water and air, one of ordinary skill inthe art would understand that various other fluids could be used.

Although embodiments of the invention are generally described in termsof use with a dental syringe, it should be appreciated that variousembodiments may be useable in applications outside of the dental syringecontext. For example, the flow regulating valves may be useable in manyapplications where flow-regulating valves, such as needle valves andball valves, are currently used, such as with nozzles for garden hoses.Accordingly, embodiments of the invention should be considered to beapplicable to many different applications and useable in many differentindustries.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

That which is claimed:
 1. A valve, comprising: a body; a flow passagewaydefined within the body; a flow-control seal positioned within the flowpassageway; a piston extending through the flow passageway and theflow-control seal, the piston defining a first direction and a seconddirection of an axis; a flow-control groove defined in the piston,wherein the flow-control groove defines a depth extending into thepiston, and wherein the flow-control groove does not extend around theentire circumference of the piston; a fluid supply conduit in fluidcommunication with a first portion of the flow passageway extending fromthe flow-control in the second direction, the fluid supply conduitconfigured to provide a fluid flow applied at the perimeter of thepiston in the first portion of the flow passageway; a fluid outletconduit in fluid communication with a second portion of the flowpassageway; a force means configured to apply a force on the piston inthe first direction along the axis; wherein the flow-control sealcontacts the body and the piston and thereby separates the first portionand the second portion of the flow passageway to substantially preventfluid communication between the first portion and the second portion ofthe flow passageway when the piston is in a first position wherein theflow-control groove is displaced from the flow-control seal in the firstdirection; wherein, when the piston is displaced in the seconddirection, opposite to the first direction to a second position, theflow-control groove extends at least partially beyond the flow-controlseal in both the first direction and the second direction, whereby thefluid supply conduit is in fluid communication with the fluid outletconduit through the first portion and the second portion of the flowpassageway; wherein the depth of the flow-control groove graduallyincreases in the first direction from a proximal end to a distal end tobe configured to gradually increase the flow of fluid between the firstportion and the second portion of the flow passageway as the piston isdisplaced in the second direction.
 2. The valve of claim 1, furthercomprising a first centering sleeve positioned within the flowpassageway, wherein the piston extends through the first centeringsleeve to thereby substantially prevent movement of the piston otherthan in the first direction and the second direction along the axis. 3.The valve of claim 2 further comprising a first retaining member, thefirst retaining member extending at least partially through the body andat least indirectly contacting the first centering sleeve to therebyrestrain movement of the first centering sleeve and the flow-controlseal at least in the first direction.
 4. The valve of claim 3 furthercomprising a second retaining member, the second retaining membercoupling to the piston in a cavity, whereby movement of the piston inthe first direction is at least partially restrained by indirect contactbetween the second retaining member and the first retaining memberthrough at least the centering sleeve and the flow-control seal.
 5. Thevalve of claim 2 wherein the first centering sleeve is positioned in thefirst portion of the flow passageway, and wherein the first centeringsleeve comprises an inlet aperture through which fluid communicationbetween the fluid supply conduit and the flow-control groove occurs whenthe piston is displaced in the second direction.
 6. The valve of claim 5further comprising a second centering sleeve positioned within thesecond portion of the flow passageway, wherein the second centeringsleeve comprises an outlet aperture through which fluid communicationbetween the flow-control groove and the fluid outlet conduit occurs whenthe piston is displaced in the second direction.
 7. The valve of claim1, wherein the force means comprises a spring configured to apply aspring force on the piston in the first direction along the axis.
 8. Thevalve of claim 7 wherein the spring is positioned within a cavity incommunication with a cavity pressure, wherein the cavity pressure isless than the pressure in the fluid supply conduit.
 9. The valve ofclaim 8, wherein the cavity pressure is ambient air pressure.
 10. Thevalve of claim 9 wherein the cavity is in communication with ambient airpressure through a pressure relief conduit.
 11. The valve of claim 1,wherein the fluid supply conduit comprises a metering screw, themetering screw comprising a cylindrical end portion which is configuredto be received by a metering cavity in the body, the metering cavitycomprising a cylindrical end cavity, wherein the cylindrical end portionis moveable from an extended position to a retracted position, whereinwhen the cylindrical end portion is in the extended position, themetering screw occupies a first occupied volume of the metering cavity,wherein when the cylindrical end portion is in the retracted position,the metering screw occupies a second occupied volume of the meteringcavity, and wherein the second occupied volume is less than the firstoccupied volume.
 12. The valve of claim 11, wherein the fluid supplyconduit is in fluid communication with the first portion of the flowpassageway when the cylindrical end portion is in the extended positionand the retracted position.
 13. The valve of claim 11, wherein thecylindrical end portion comprises a compressible end portion, whereinthe compressible end portion is configured to compress against the bodyand radially expand when the cylindrical end portion is in the extendedposition to substantially prevent flow of a fluid through the meteringcavity.
 14. The valve of claim 1, wherein the flow-control groove isconfigured to permit increasing flow of fluid through the valve as thepiston is displaced in the second direction.
 15. The valve of claim 1,wherein the force means comprises a fluid source configured to supply afluid force to the piston.
 16. The valve of claim 1, wherein the totalarea of the piston perpendicular to the axis which is exposed to forcefrom the fluid in the second direction is greater than the total area ofthe piston perpendicular to the axis which is exposed to force from thefluid in the first direction.
 17. The valve of claim 1, wherein thetotal area of the piston perpendicular to the axis which is exposed toforce from the fluid in the second direction is equal to the total areaof the piston perpendicular to the axis which is exposed to force fromthe fluid in the first direction.
 18. The valve of claim 1, wherein thetotal area of the piston perpendicular to the axis which is exposed toforce from the fluid in the second direction is less than the total areaof the piston perpendicular to the axis which is exposed to force fromthe fluid in the first direction.
 19. The valve of claim 1 furthercomprising a flow passageway end seal configured to substantiallyprevent fluid from escaping out of the flow passageway in the firstdirection.
 20. A method of controlling a flow of fluid, comprising:providing a valve comprising a piston defining a flow-control groove andextending through a flow passageway defined in a body along a firstdirection and a second direction of an axis and a flow-control sealpositioned within the flow passageway, wherein the flow-control groovedefines a depth extending into the piston, wherein the flow-controlgroove does not extend around the entire circumference of the piston,wherein the flow-control seal separates the flow passageway into a firstportion, extending from the flow-control seal in the second direction,and having a fluid flow supplied thereto, and a second portion;providing a force means configured to apply a force to the piston in thefirst direction along the axis defined by the piston; displacing thepiston in the second direction along the axis opposite to the firstdirection to bring the first portion and the second portion of the flowpassageway into fluid communication through the flow-control groove andthereby allow the fluid to flow through the valve, wherein the depth ofthe flow-control groove gradually increases in the first direction froma proximal end to a distal end so as to gradually increase the flow offluid between the first portion and the second portion of the flowpassageway as the piston is displaced in the second direction; releasingthe piston, whereby the force means displaces the piston including theflow-control groove in the first direction and thereby prevents fluidcommunication between the first portion and the second portion of theflow passageway and prevents flow of the fluid through the valve. 21.The method of claim 20, wherein the valve further comprises a firstcentering sleeve positioned within the flow passageway, wherein thepiston extends through the first centering sleeve to therebysubstantially prevent movement of the piston other than in the firstdirection and the second direction along the axis, wherein the firstcentering sleeve is positioned in the first portion of the flowpassageway, and wherein the first centering sleeve comprises an inletaperture through which fluid communication between the fluid supplyconduit and the flow-control groove occurs when the piston is displacedin the second direction.
 22. A valve, comprising: a body; a flowpassageway defined within the body; a flow-control seal positionedwithin the flow passageway; a piston extending through the flowpassageway and the flow-control seal, the piston defining a firstdirection and a second direction of an axis; a flow-control groovedefined in the piston, wherein the flow-control groove defines a depthextending into the piston, and wherein the flow-control groove does notextend around the entire circumference of the piston; a fluid supplyconduit in fluid communication with a first portion of the flowpassageway extending from the flow-control in the second direction, thefluid supply conduit configured to provide a fluid flow applied at theperimeter of the piston in the first portion of the flow passageway; afluid outlet conduit in fluid communication with a second portion of theflow passageway; a force means configured to apply a force on the pistonin the first direction along the axis; and a first centering sleevepositioned within the flow passageway, wherein the piston extendsthrough the first centering sleeve to thereby substantially preventmovement of the piston other than in the first direction and the seconddirection along the axis, wherein the first centering sleeve ispositioned in the first portion of the flow passageway, and wherein thefirst centering sleeve comprises an inlet aperture through which fluidcommunication between the fluid supply conduit and the flow-controlgroove occurs when the piston is displaced in the second direction;wherein the flow-control seal contacts the body and the piston andthereby separates the first portion and the second portion of the flowpassageway to substantially prevent fluid communication between thefirst portion and the second portion of the flow passageway when thepiston is in a first position wherein the flow-control groove isdisplaced from the flow-control seal in the first direction; wherein,when the piston is displaced in the second direction, opposite to thefirst direction to a second position, the flow-control groove extends atleast partially beyond the flow-control seal in both the first directionand the second direction, whereby the fluid supply conduit is in fluidcommunication with the fluid outlet conduit through the first portionand the second portion of the flow passageway.
 23. The valve of claim 22further comprising a second centering sleeve positioned within thesecond portion of the flow passageway, wherein the second centeringsleeve comprises an outlet aperture through which fluid communicationbetween the flow-control groove and the fluid outlet conduit occurs whenthe piston is displaced in the second direction.